you can forward your faxes to several destinations, this should not be a problem. I'm quite sure that when you choose your destinations in CentreWare, the boxes will get ticked of if it should not work together with another service.
Is is possible to forward received faxes to email and SMB at the same time with WorkCentre 3315dn?
User manual says:
When you forward a fax to an e-mail address or an FTP or SMB server, you must use CentreWare Internet Services to set up the destination details. You can forward a fax to a total of five destinations.
Refer to the System Administrator Guide for instructions.
Note: Some options may be unavailable depending on your machine configuration.
System administrator guide says:
You can choose to forward faxes to one of the following destinations:
So, can I forward an incoming fax to five destinations or to just one?